We currently use about 700 gallons of #2 oil to heat our home and supply our domestic hot water. We have an oil fired boiler and it runs our baseboard for heat and a coil for our hot water. Our 1,250 sq ft home is insulated, but the wall insulation has settled over time and could use topping off and our attic insulation is modest at best as well. If we had a contractor come in and blow insulation in our walls that could bring our oil usage down by a solid 10%. If I add more insulation in our attic, we could save another 5%. Replacing our windows would get us another 5% down on oil. That brings us down to 560 gallons per year.
At some point we need to replace our aging 23 year old boiler with a newer unit. We are planning on going with a direct-vent boiler so we can free up our chimney for wood stove use later. Direct vent boilers in our size rate at 86% efficiency, our boiler is 84% efficient as of our last cleaning this fall. This new boiler alone would save us another 2%, dropping us down to 550 gallons per year.
Add in an outdoor temp reset on the boiler for another 5% savings and that brings us in at 522.5 gallons per year (we’ll round up to 525). Now add in a small Jotul 602 CB like we’ve been considering for supplemental heat. Burn 3 cords of softwood per year (this is what we have available), and that will save another 270 gallons of oil. That brings us down to a measly 255 gallons of oil per year. A bit over 1/3 of what we currently consume now and we would still be comfortably warm all winter and have all the hot water we would want all year.
Good news and bad news. The good news is that it turns out there are two larger stoves that fit our alcove. The Jotul 100 QT and the Jotul F 3 CB. The bad news is that our ceiling height for the Jotul 602 CB isn’t approved (for alcove installation), and the Jotul 100 QT has a kind of poor design that can allow logs to roll out if you open the door while it is burning. So that leaves the F 3 CB, the largest alcove approved stove by Jotul.
This is sort of the other good news. The F 3 CB puts out 42,000 btu, enough to heat our entire home even when it is -20F outside! It has the best alcove ratings for tight installations due to it’s design, it appears to have a well designed firebox as well (can’t allow logs to roll out), and it has lots of cast iron on the glass (makes me feel safer and I like the looks). The down side is it is more expensive, and is less good for cooking (or so I’ve heard) as compared to the 602.
This would give us the btu power to heat our home almost entirely with wood if we so chose – also a plus.